The negative effects of invasive plants on ecosystem multifunctionality weaken with increase in temperature

Invasive plants introduced outside their native ranges by human activities are posing significant threats to ecosystem functions. Nevertheless, the effects driven by plant invasions are scantily described in relation to the ability of ecosystems providing multiple functions simultaneously (i.e., ecosystem multifunctionality, EMF). Given that climate warming has been shown to influence the ecological consequences of invasive plants, how these impacts vary along temperature gradients also requires further in-depth investigation. Meanwhile, the impact of indigenous species provides a better reference for assessing the consequences of invasive species. In this study, we collected plant and soil samples from beneath either invasive Xanthium species ( Xanthium spinosum L. and Xanthium italicum Moretti) or indigenous Xanthium species ( Xanthium sibiricum Patr.) and their adjacent areas without Xanthium at 12 sites in northwest China. We found that invasive Xanthium was associated with lower EMF compared to the ‘without Xanthium ’ treatment, while indigenous Xanthium exhibited a non-significant upward trend. The negative association between invasive Xanthium and EMF became weaker with increasing temperature, while there was no significant interaction between indigenous Xanthium and warming. According to the results of piecewise structural equation modelling (pSEM), abiotic factors were more strongly associated with EMF responses in invaded ecosystems, whereas biotic factors showed stronger associations in indigenous ecosystems. Our study highlights that the negative association between invasive plants and EMF is less pronounced with increasing temperature. This may provide a theoretical basis for understanding the consequences of plant invasions and for managing invasive plants under different climatic conditions.